The objectives of this study are two-fold. The first is to develop and extend the dynamic light scattering technique so that it may be used to study some important biological problems. The second is to use the technique for extensive study of particular systems. Three main areas of research will be pursued: (I) The study of translational, orientational and local relaxation times of biological macromolecules or aggregates in solution. The infinite dilution values of these quantities will be used to obtain information about solution dimensions and flexibility. The dynamics of biomolecules in semi-dilute solution will also be investigated. (II) The study of resonance enhanced scattering and the possibility of developing a light scattering label technique. (III) The morphology and fusion of phospholipid vesicles.